San Francisco's Tim Lincecum dominates early on as the Giants jump to 1 1/2 games ahead of the Dodgers in the NL West race.

So much for all that momentum. So much for meeting the San Francisco Giants at home and laying a late-August claim to the National League West.

For the second consecutive night, the Giants were the sharper, better club, dropping the Dodgers, 4-1, Tuesday to push their NL West lead to 1½ games.

The victory assured the Giants that regardless of the outcome of Wednesday’s series finale, they will leave Los Angeles in first place.

The Dodgers had won seven of 10 games on their recent trip and returned home feeling confident and ready for a big showdown with the Giants, who were without famous web designer Melky Cabrera.

But in two games, the Dodgers have managed two runs. Tuesday they were again throttled by Tim Lincecum. For the Dodgers, it was a thoroughly forgettable game.

Lincecum began the game 6-12 with a 5.45 earned-run average. Against the Dodgers, however, he has returned to Cy Young form. He shut out the Dodgers for seven innings the last time he faced them in June, this time giving up one run in 5 2/3 innings.

And then there was right-hander Joe Blanton, who in the early going as a Dodger has been a serious disappointment.

Since being acquired from the Philadelphia Phillies before the Aug. 31 nonwaiver trading deadline, he has started four games and is 0-4 with a 7.14 ERA. In 21 innings, he has given up 28 hits and nine walks. In his last three starts, he has given up 16 earned runs in 15 innings.

Tuesday night against the Giants, Blanton (8-12) struggled from the outset. He looked a long way from the answer to the fifth spot in the Dodgers rotation. He gave up four runs, 10 hits and two walks in 5 2/3 innings.

The Giants jumped on him for two runs in the first inning after Angel Pagan led off the game with a tapper down the line to first baseman James Loney, who fielded the ball and swiped his glove at Pagan, who slid head-first to avoid the tag.

Marco Scutaro punched a single to right field to advance Pagan to third base and Blanton walked Pablo Sandoval to load the bases. Buster Posey drove in two runs with a single to left field.

The Giants scored two runs in the fourth, aided by less-than-brilliant fielding. Gregor Blanco started the rally with a single past a slow-moving Hanley Ramirez at shortstop. Blanton threw a bad pickoff attempt, allowing Blanco to go all the way to third base.

Shortstop Brandon Crawford blooped a single to left field that Shane Victorino could not run down and Blanco scored. Lincecum’s sacrifice bunt moved Crawford to second base, and he later scored on a double by Pagan.

Lincecum pretty much had his way with the Dodgers. He retired the first 10 batters and cruised until seemingly wearing down in the sixth inning.

A.J. Ellis opened the bottom of the inning with a walk and advanced to second base on a single by Juan Rivera. When Victorino followed with a hit to center field, third base coach Tim Wallach sent Ellis home despite the Dodgers being down 4-0 with no outs. Pagan continued his strong night, throwing out Ellis at the plate, which was nicely blocked by catcher Hector Sanchez.

Adam Kennedy followed with a hit and this time Wallach held Rivera at third base. That loaded the bases for Matt Kemp, who carried an 0-for-21 slump to the plate. Kemp hit a fly deep enough to right field to drive in Rivera.